Semiconductor laser light source having an edge-emitting semiconductor body

ABSTRACT

A semiconductor laser light source comprising an edge-emitting semiconductor body ( 10 ) is provided. The semiconductor body ( 10 ) contains a semiconductor layer stack ( 110 ) having an n-type layer ( 111 ), an active layer ( 112 ) and a p-type layer ( 113 ) which is formed for generating electromagnetic radiation which comprises a coherent portion ( 21 ). The semiconductor laser light source is formed for decoupling the coherent portion ( 21 ) of the electromagnetic radiation from a decoupling surface ( 101 ) of the semiconductor body ( 10 ) which is inclined with respect to the active layer ( 112 ). The semiconductor body ( 10 ) comprises a further external surface ( 102 A,  102 B,  102 C) which is inclined with respect to the decoupling surface ( 101 ) and has at least one light-diffusing sub-region ( 12, 12 A,  12 B,  12 C,  120 A,  120 B) which is provided in order to direct a portion of the electromagnetic radiation generated by the semiconductor layer stack ( 110 ) in the direction towards the further external surface ( 102 A,  102 B,  102 C).

The present disclosure relates to a semiconductor laser light sourcehaving an edge-emitting semiconductor body.

A semiconductor laser light source having an edge-emitting semiconductorbody is disclosed e.g. in document WO 2009/080012 A1.

A problem with conventional semiconductor laser light sources is thatdeviations in the far field of the emitted laser radiation from theGaussian beam profile can lead to inadequate reproductioncharacteristics.

It is an object of the present disclosure to specify a semiconductorlaser light source which has the least possible disturbance in the farfield and can be operated efficiently with particularly stable outputpower.

This object is achieved by a semiconductor laser light source inaccordance with claim 1. Advantageous embodiments and developments ofthe semiconductor laser light source are described in the dependentclaims, the disclosure content of which is hereby explicitlyincorporated into the description.

A semiconductor laser light source is specified. The semiconductor laserlight source comprises a semiconductor body. The semiconductor bodycontains a semiconductor layer stack having an n-type layer, an activelayer and a p-type layer. The direction in which the n-type layer, theactive layer and the p-type layer follow one another is definedhereinafter as the “vertical direction”.

Each of these layers can be composed of a plurality of individuallayers. For example, the n-type layer can comprise an n-typesemiconductor substrate and a likewise n-type semiconductor layer whichis produced on the n-type semiconductor substrate and in particular isepitaxially grown thereon. The active layer contains e.g. a sequence ofindividual layers, by means of which a quantum well structure, inparticular a single quantum well structure (SQW) or multiple quantumwell structure (MQW) is formed.

The semiconductor layer stack is formed for generating anelectromagnetic radiation which comprises a coherent portion. Forexample, the semiconductor laser light source, preferably thesemiconductor body, contains a resonator for this purpose. Inparticular, the coherent portion of the electromagnetic radiation islaser radiation, e.g. infrared, visible or ultraviolet laser radiation.The coherent portion can be e.g. laser radiation in the fundamental modeof the resonator.

For example, the semiconductor body is based upon the semiconductormaterial InGaN. In this case, it can emit e.g. electromagneticradiation, the coherent portion of which has an intensity maximum in theblue or green spectral range. Alternatively, the semiconductor layerstack can be based e.g. upon the semiconductor material InGaAs. In thiscase, the coherent portion has e.g. an intensity maximum in the infraredspectral range.

The electromagnetic radiation emitted by the semiconductor layer stackduring operation of the semiconductor laser light source contains inparticular a further portion which is not encompassed by the coherentportion. For example, the semiconductor layer stack emits a furthercoherent portion of electromagnetic radiation and/or an incoherentelectromagnetic radiation. The further coherent portion can be e.g.higher order laser modes, e.g. parasitic substrate and/or waveguidemodes.

The semiconductor body is in particular an edge-emitting semiconductorbody. This means that the semiconductor body comprises a decouplingsurface, sometimes also called a “facet”, which is inclined towards theactive layer, in particular is perpendicular to the active layer. In anexpedient manner, the semiconductor laser light source is formed fordecoupling the coherent portion of the electromagnetic radiation fromthe decoupling surface of the semiconductor body.

In the case of one embodiment, the edge-emitting semiconductor body hasa transverse lateral surface opposite to the decoupling surface. Thetransverse lateral surface is preferably mirror-coated and formstogether with the decoupling surface the resonator. Furthermore, thesemiconductor body can have two mutually opposite longitudinal sidesurfaces which extend in particular from the decoupling surface towardsthe transverse lateral surface. The decoupling surface, the transverselateral surface and/or the longitudinal side surfaces extend inparticular from a top-side external surface to an n-side externalsurface—opposite to the p-side external surface—of the semiconductorbody.

In the case of one embodiment, the semiconductor body comprises a ridgewhich is designated hereinafter as a waveguide ridge. The waveguideridge is formed by the semiconductor layer stack and has a mainextension direction which extends preferably in the direction of anormal vector onto the decoupling surface. A “ridge” in accordance withthe present disclosure is formed in particular in such a manner that, asseen in a plan view of the p-side external surface of the semiconductorbody, the ridge has in its main extension direction at least twice theextension, preferably at least five-times the extension, asperpendicular thereto. The waveguide ridge extends e.g. from thedecoupling surface to the transverse lateral surface of thesemiconductor body. It is formed e.g. by structuring a p-side surface ofthe semiconductor body.

The semiconductor body comprises a further external surface which isinclined towards the decoupling surface and in particular isperpendicular to the decoupling surface. For example, the furtherexternal surface is one or a plurality of the following surfaces:longitudinal side surface, p-side external surface, n-side externalsurface.

Moreover, the semiconductor body has at least one light-diffusingsub-region which is provided in order to direct a portion of theelectromagnetic radiation generated by the semiconductor layer stack inthe direction of the further external surface. For example, thelight-diffusing sub-region diffuses the further coherent portion of theelectromagnetic radiation and/or the incoherent portion of theelectromagnetic radiation at least partly in the direction of thefurther external surface.

The light-diffusing sub-region can additionally direct electromagneticradiation, which is generated by the semiconductor layer stack, in thedirection towards other external surfaces of the semiconductor body, inparticular by means of scattering. In an expedient manner, it issuitable for reducing the intensity—impinging upon the decouplingsurface—of the portion of electromagnetic radiation not encompassed bythe coherent portion. For example, electromagnetic radiation fromparasitic substrate and/or waveguide modes can be directed away from thedecoupling surface by means of the light-diffusing sub-region.

In this context, the fact that the semiconductor body comprises at leastone light-diffusing sub-region is understood to mean that it comprisesprecisely one light-diffusing sub-region or that it comprises aplurality of light-diffusing sub-regions. For example, it comprises afirst light-diffusing sub-region and a second light-diffusing sub-regionwhich are provided in each case in order to direct a portion of theelectromagnetic radiation, which is generated by the semiconductor layerstack, in the direction towards the further external surface. Thesemiconductor body can also comprise different light-diffusingsub-regions which are provided in order to direct electromagneticradiation, which is emitted by the semiconductor layer stack, todifferent further external surfaces of the semiconductor body.

The inventors have established that the intensity of the portion of theelectromagnetic radiation which is diffused by the at least onelight-diffusing sub-region in the direction towards the further externalsurface changes linearly or at least approximately linearly with theintensity of the coherent portion decoupled by the decoupling surface.The diffused radiation directed by the light-diffusing sub-regiontowards the external surface can thus advantageously be measured andpreferably used for controlling or regulating an operating currentthrough the semiconductor layer stack.

At the same time, it is possible in this manner to achieve aparticularly high beam quality of the laser radiation radiated from thedecoupling surface. For example, the fraction of higher order lasermodes is particularly small which means that the beam profile deviatesto a particularly small extent from a Gaussian form. In particular, thebeam profile does not comprise, or comprises only slight, side peaks orwaves (so-called “ripples”). The light-diffusing sub-regionadvantageously in particular does not have an unfavourable effect upontypical laser characteristics, such as lasing threshold and slope.

In addition, it is not necessary to lower the mirror-coating of thetransverse lateral surface which is opposite to the decoupling surface,in order to be able to measure the intensity of the coherent portion ofthe electromagnetic radiation, as is typically the case withconventional semiconductor laser light sources.

In accordance with at least one embodiment, the at least onelight-diffusing sub-region extends starting from the p-type layer orstarting from the n-type layer into the active layer or through theactive layer. In this manner, lateral disturbances of the beam profilecan be reduced in a particularly effective manner.

In the case of a further embodiment, in which the at least onelight-diffusing sub-region extends at least in the p-type layer, it islaterally spaced apart from the waveguide ridge at least in the regionof the p-type layer. In the case of one development, the lateral spacedinterval is ≦20 μm, preferably ≦5 μm and particularly preferably ≦2 μm.In particular, if the semiconductor laser light source comprises aplurality of light-diffusing sub-regions, each of the sub-regionsextending at least in the p-type layer is laterally spaced apart fromthe waveguide ridge at least in the region of the p-type layer.

In the case of the semiconductor laser light source in accordance withthis embodiment, the height of the waveguide ridge can be selected to beparticularly big, whereby it is advantageously possible to achieve aparticularly small p-side current expansion. Without the light-diffusingsub-region, in order to suppress higher order laser modes the shape ofthe waveguide ridge would have to be selected in such a manner that onlythe fundamental mode of the edge-emitting semiconductor body can beginto oscillate. The waveguide ridge should then be able to have only acomparatively smaller height. However, this can lead to an undesirablyhigh threshold current by reason of a comparatively large p-side currentexpansion.

Furthermore, e.g. in the case of the semiconductor laser light source inaccordance with this embodiment, it is possible to omit the use ofabsorber layers at the side of the waveguide ridge, which absorberlayers also damp the fundamental mode of the laser radiation. It is thuspossible to achieve a particularly high level of efficiency.

In the case of one embodiment, the first light-diffusing sub-regionextends e.g. at least in the p-type layer, in the case of onedevelopment it extends from the p-type layer into the active layer orthrough the active layer into the n-type layer.

In the case of this embodiment, the second light-diffusing sub-regionextends at least in the n-type layer. In the case of one development, itextends exclusively in the n-type layer, wherein it extends e.g. over atleast 10%, preferably over at least 30% and particularly preferably overat least 50% of a thickness of the n-type layer.

In the case of one development, the first light-diffusing sub-region andthe second light-diffusing sub-region do not overlap or overlap onlypartially in the vertical direction as seen in a plan view of thedecoupling surface. In the case of another development, the first andthe second light-diffusing sub-regions overlap as seen in a plan view ofthe p-side outer surface. In this case, the second light-diffusingsub-region can overlap with the waveguide ridge and the firstlight-diffusing sub-region can be laterally spaced apart from thewaveguide ridge.

By means of the first and the second light-diffusing sub-regions, it ispossible to achieve e.g. a particularly good beam quality of thecoherent electromagnetic radiation, which is decoupled from thedecoupling surface, both in a lateral direction and in the verticaldirection. In this case, the light-diffusing sub-region which extends inthe n-type layer contributes e.g. to the diffusion of laser modes whichare guided in the n-type layer, in particular in the substrate, so thata particularly good radiation characteristic can be achieved in thevertical direction with the second light-diffusing sub-region.

In accordance with at least one embodiment, in order to form the atleast one light-diffusing sub-region a cavity is formed in thesemiconductor body. The cavity can be produced e.g. by means of a wetetching method, a dry etching method or by means of spatially selectiveepitaxial growth. The cavity can be filled with gas, in particular itcan be filled with air. In particular, the cavity is partially orcompletely filled with a material which comprises a refractive indexwhich is different from the surrounding semiconductor material.

In the case of another embodiment, the at least one light-diffusingsub-region is formed by means of a material composition and/or by meansof a crystal structure which deviates from the material composition orcrystal structure which a region of the semiconductor body adjoining thelight-diffusing sub-region comprises. For example, the light-diffusingsub-region can comprise a semiconductor composition or doping which isdifferent from the adjoining region, or it can be provided with defects,e.g. by means of a so-called stealth-dicing method.

In the case of another embodiment, the at least one light-diffusingsub-region is formed by means of a transverse ridge which is applied atthe side of the waveguide ridge onto the semiconductor layer stack or isformed by the semiconductor layer stack. The transverse ridge has inparticular a main extension direction which is different from the mainextension direction of the waveguide ridge. In the case of onedevelopment, the main extension directions of the waveguide ridge andtransverse ridge extend perpendicularly with respect to one another.

In the case of one development, the transverse ridge is laterally spacedapart from the waveguide ridge.

If the transverse ridge is formed by the semiconductor layer stack itcan be produced—like the waveguide ridge itself—by means of an etchingmethod by structuring the p-side surface of the semiconductor layerstack. However, the material of the transverse ridge does not need to bea semiconductor material, another material can also be applied onto thesemiconductor layer stack, in order to form the transverse ridge. Forexample, in this case the transverse ridge preferably has a refractiveindex which is different from the refractive index of the waveguideridge.

In the case of one development, the semiconductor laser light sourcecomprises a plurality of transverse ridges which follow one another inthe direction of the main extension direction of the waveguide ridge.Preferably, they follow one another periodically and form in particulara distributed Bragg reflector (DBR). In the case of another development,transverse ridges are arranged on both sides next to the waveguideridge. For example, as seen in a plan view of the p-side externalsurface, two transverse ridges which are arranged on different sides ofthe waveguide ridge follow one another in each case in a directionperpendicular to the main extension direction of the waveguide ridge.

In accordance with a further embodiment, the at least onelight-diffusing sub-region has a main extension plane which extends inan inclined manner with respect to the vertical direction, in which then-type layer, the active layer and the p-type layer follow one another.For example, the main extension plane extends in an oblique manner withrespect to the vertical direction and in parallel with the mainextension direction of the waveguide ridge which in particular is inparallel with the normal vector onto the decoupling surface. In the caseof one development, the light-diffusing sub-region extends from thedecoupling surface as far as the opposite transverse lateral surface.

By means of a light-diffusing sub-region whose main extension planeextends in an inclined manner with respect to the vertical direction,undesired radiation can be diffused away from the waveguide ridge in aparticularly effective manner.

The main extension plane of the light-diffusing sub-region is spanned inparticular by the two directions in which it has its largest dimensions.If the light-diffusing sub-region is in the form e.g. of a cuboid, itsmain extension plane is spanned by the directions of the two longestedges. The dimensions of the light diffusing sub-region in the mainextension plane are e.g. at least twice as large, preferably at leastfive times as large, as its dimension perpendicular to the mainextension plane.

In the case of another embodiment, the at least one light-diffusingsub-region has a main extension plane which extends in an inclinedmanner with respect to the normal vector onto the decoupling surface. Inparticular, it extends in an oblique manner with respect to the normalvector onto the decoupling surface and in parallel with the verticaldirection.

In the case of one embodiment, the light-diffusing sub-region is formedin a U-shaped manner as seen in a plan view of its main extension plane.Such an embodiment is particularly well suited for a light-diffusingsub-region whose main extension plane extends in an oblique manner withrespect to the normal vector onto the decoupling surface and inparticular in parallel with the vertical direction.

Preferably, the U-shaped, light-diffusing sub-region encloses a sectionof the active layer. In this manner, an undesired portion of theelectromagnetic radiation generated by the semiconductor layer stack canbe shielded in a particularly effective manner from the decouplingsurface and can be directed towards the further external surface.

It is possible to achieve a particularly good shielding effect if the atleast one light-diffusing sub-region or at least one of thelight-diffusing sub-regions is arranged in the vicinity of thedecoupling surface. The phrase “in the vicinity of the decouplingsurface” means in particular that the spaced interval of thelight-diffusing sub-region with respect to the transverse lateralsurface is at least twice as large, preferably at least four times aslarge as the spaced interval with respect to the decoupling surface.

In accordance with at least one embodiment, the semiconductor laserlight source comprises a photodiode which is arranged on or above thefurther external surface of the semiconductor body. In the case ofanother embodiment, the photodiode is integrated monolithically into thesemiconductor body. The photodiode expediently generates an electricalsignal in dependence upon the intensity of the electromagnetic radiationreceived thereby.

In the case of the semiconductor laser light source in accordance withthe present disclosure, the photodiode can advantageously be arrangedlaterally next to the waveguide ridge, so that a particularly smalldimension of the semiconductor laser light source can be achieved in themain extension direction of the waveguide ridge.

A photodiode which is integrated monolithically into the semiconductorbody is particularly cost-effective and space-saving and does notrequire any further assembly steps after completion of the semiconductorbody. By means of the monolithic integration, a particularly largefraction of the diffused light deflected from the light-diffusingsub-region can be absorbed by the photodiode.

The semiconductor laser light source is formed in particular for thepurpose of irradiating the photodiode with a portion of theelectromagnetic radiation generated by the semiconductor layer stack. Inan advantageous manner, no reduction in the mirror-coating of thetransverse lateral surface is required for this purpose. By means of thelight-diffusing sub-region, a satisfactory incidence of radiation ontothe photodiode can still be achieved.

Therefore, in the case of one development, if the photodiode is arrangedon or above the further external surface of the semiconductor body, thenas seen in a plan view of the further external surface at least oneregion of the further external surface which overlaps with thephotodiode is roughened or provided with macroscopic decouplingstructures. In this context, decoupling structures are defined as“macroscopic” if they are 10 μm or more at least in one dimension.

In accordance with one development, if the photodiode is integratedmonolithically into the semiconductor body, then a material having arefractive index which is larger than a refractive index of thephotodiode and than a refractive index of the active layer is arrangedbetween the photodiode and the active layer. In particular, the materialis an isolator.

In the case of one embodiment, the photodiode extends longitudinally ofthe waveguide ridge over a large part of the semiconductor body, so thatits length is in particular 80% or more of the length of the waveguideridge—that is to say, of its dimension in the main extension direction.In the case of another embodiment, the photodiode is arranged in thevicinity of the decoupling surface, in particular its spaced intervalwith respect to the transverse lateral surface opposite to thedecoupling surface is at least twice as large, preferably at least fourtimes as large, as the spaced interval with respect to the decouplingsurface.

A photodiode which does not extend over a large part of the length ofthe semiconductor body can react, by reason of its lower capacity, in aparticularly rapid manner to intensity changes of the electromagneticradiation generated by the semiconductor layer stack.

In the case of a further embodiment, the semiconductor laser lightsource comprises an electrical circuit. The electrical circuit isprovided e.g. to supply operating current to the semiconductor layerstack. In addition, it is preferably provided in order to evaluate theelectrical signal of the photodiode and, during operation of thesemiconductor laser light source, to control the operating currentthrough the semiconductor layer stack in dependence upon the electricalsignal of the photodiode. For this purpose, the electrical circuit is,in an expedient manner, electrically connected to the semiconductorlayer stack and to the photodiode.

The semiconductor laser light source is provided e.g. for use in a laserprojector, for which semiconductor bodies based on InGaN areparticularly well suited. It can also be used in a 3D scanner, for whichsemiconductor bodies based on InGaAs are particularly well suited.

Laser projection applications and 3D scanning applications placeconsiderable requirements on focus capability and/or collimationcapability of the laser light source. For this purpose, a good beamquality, in particular a Gaussian or virtually Gaussian beam profile, ascan be achieved with the semiconductor laser light source in accordancewith the present disclosure, is particularly advantageous.

The semiconductor laser light source comprising the photodiode and theelectrical circuit advantageously has a particularly long service life.The service life defines in particular the operating time of thesemiconductor laser light source until a specified tolerance of one ofits operating parameters, in particular light intensity and/or lightingcurrent, is exceeded. In the case of an example of the operatingprocedure of the semiconductor laser light source, the electricalcircuit detects, by means of the signal of the photodiode, a deviationin the light intensity or lighting current of the semiconductor laserlight source from a specified desired value and changes the operatingcurrent through the semiconductor layer sequence in dependence upon thesignal of the photodiode such that the deviation is minimised.

Further advantages and advantageous embodiments and developments of thesemiconductor laser light source are apparent from the followingexemplified embodiments illustrated in conjunction with the figures, inwhich:

FIG. 1A shows a schematic plan view of a semiconductor body of a firstlaser light source,

FIG. 1B shows a schematic cross-section of the semiconductor body ofFIG. 1A in the sectional plane B-B,

FIG. 2 shows a schematic plan view of a semiconductor body of a secondlaser light source,

FIG. 3A shows a schematic plan view of a semiconductor body of a thirdlaser light source,

FIG. 3B shows a schematic cross-section of the semiconductor body ofFIG. 3A in the sectional plane B-B,

FIG. 3C shows a schematic cross-section of the semiconductor body ofFIG. 3A in the sectional plane C-C,

FIG. 4A shows a schematic cross-section of a semiconductor body of afourth laser light source,

FIG. 4B shows a schematic plan view of the semiconductor body of FIG.4A,

FIG. 5A shows a schematic plan view of a semiconductor body of a fifthlaser light source,

FIG. 5B shows a schematic cross-section of the semiconductor body ofFIG. 5A,

FIG. 5C shows a schematic cross-section of a semiconductor body inaccordance with one variant of the fifth laser light source,

FIG. 6 shows a schematic perspective view of a sixth laser light source,

FIG. 7 shows a schematic cross-section of a seventh laser light source,

FIG. 8 shows a schematic cross-section of an eighth laser light source,

FIG. 9 shows a schematic perspective view of a ninth laser light source,

FIG. 10 shows a schematic cross-section of a tenth laser light source,

FIG. 11 shows a schematic plan view of an eleventh laser light source,

FIG. 12 shows a schematic plan view of a twelfth laser light source,

FIG. 13 shows a section of the semiconductor body of the eleventh laserlight source in a schematic plan view of its active layer,

FIG. 14 shows a schematic cross-section of the eleventh laser lightsource.

Identical or similar elements, or elements acting in an identicalmanner, are provided with the same reference numerals in the figures.The figures and the size ratios of the elements illustrated in thefigures with respect to each other are not to be regarded as being toscale. Rather, individual elements may be illustrated excessively largeto provide a clearer illustration and/or for ease of understanding.

FIG. 1A illustrates a schematic plan view of a semiconductor body 10 ofa laser light source in accordance with a first exemplified embodiment.

FIG. 1B illustrates a schematic cross-section of the semiconductor body10 of the laser light source in accordance with the first exemplifiedembodiment in the plane B-B which is indicated in FIG. 1A.

The semiconductor body 10 contains a semiconductor layer stack 110 whichis formed by an n-type layer 111, an active layer 112 and a p-type layer113 which follow one another in this sequence in a direction V which isdesignated as the vertical direction.

The n-type layer 111, the active layer 112 and/or the p-type layer 113can each be formed as layer sequences. For example, the n-type layer 111can contain a growth substrate and a semiconductor layer which isepitaxially deposited thereon. In particular, the semiconductor layerstack contains waveguide layers which include the active layer 112 forguiding the electromagnetic radiation generated therein. Suchsemiconductor layer stacks 110 are known in principle to the personskilled in the art and therefore will not be explained in greater detailat this juncture. An example of the structure of such a semiconductorlayer stack 110 is described in document WO 2009/080012 A1, thedisclosure content of which is, in this regard, hereby incorporated intothe present application by reference.

The semiconductor body 10 is defined by a plurality of externalsurfaces: a decoupling surface 101, a mirror-coated transverse lateralsurface 103 opposite to the decoupling surface, two oppositelongitudinal lateral surfaces 102A, a p-side external surface 102B andan n-side external surface 102C. The decoupling surface 101, thelongitudinal lateral surface 102A and the transverse lateral surface 103are e.g. in parallel with the vertical direction V. The longitudinallateral surfaces 102A adjoin e.g. the decoupling surface 101 and thetransverse lateral surface 103 and in particular are perpendicularthereto. The longitudinal lateral surfaces 102A, the decoupling surface101 and the transverse lateral surface 103 extend in particular from thep-side external surface 102B to the n-side external surface 102C.

The semiconductor layer stack 110 is formed for generatingelectromagnetic radiation which comprises a coherent portion 21. Inparticular, a resonator for the electromagnetic radiation is formed bythe decoupling surface 101 together with the metal-coated transverselateral surface 103.

For example, in order to achieve beam guidance of the electromagneticradiation in the direction of a surface normal N onto the decouplingsurface 101, the semiconductor layer stack 110 can comprise a waveguideridge 114 which extends from the decoupling surface 101 to the oppositetransverse lateral surface 103. Therefore, the main extension directionS of the waveguide ridge 114 is in particular in parallel with thesurface normal N onto the decoupling surface 101 and perpendicular tothe vertical direction V.

The semiconductor body 10 is formed for decoupling the coherent portion21 of the electromagnetic radiation, which is generated by thesemiconductor layer stack 110, from the decoupling surface 101. Inparticular, the decoupling surface 101 is in parallel with the verticaldirection. During production of the semiconductor body, a breakingmethod can be used, in which the semiconductor body is separated fromthe wafer composite with the decoupling surface 101 being exposed. Inthe case of this method, it can be the case that the breaking edge isonly approximately in parallel with the vertical direction. Thedecoupling surface 110 is also perpendicular or virtually perpendicularto the active layer 110. Such edge-emitting semiconductor bodies 10 areknown in principle to the person skilled in the art—e.g. from WO2009/080012 A1 which in this regard is already incorporated byreference—and therefore will not be explained in greater detail at thisjuncture.

The semiconductor body 10 of the semiconductor laser light source inaccordance with the present first exemplified embodiment comprises aplurality of light-diffusing sub-regions 12. The light-diffusingsub-regions 12, 12A, 12B, 12C are provided in order to diffuse a portionof the electromagnetic radiation generated by the semiconductor layerstack 110. In particular, they are provided in order to direct a portionof the electromagnetic radiation in the direction towards a furtherexternal surface of the semiconductor body 10 which is different fromthe decoupling surface 101—in the present case, towards the longitudinallateral surfaces 102A. The radiation diffused by one of thelight-diffusing sub-regions 12 towards one of the longitudinal lateralsurfaces 102A is designated in FIG. 1A by the reference numeral 22.

The outer contours of the light-diffusing sub-regions 12 can havedifferent shapes. By way of example, in the plan view of the p-sideexternal surface 102B of FIG. 1A a first light-diffusing sub-region 12Ais characterised by a circular outer contour, a second light-diffusingsub-region 12B has e.g. a rectangular outer contour as seen in a planview of the p-type layer 113, a third light-diffusing sub-region 12C hasan oval, in particular elliptical, outer contour.

The light-diffusing sub-regions 12 in the case of this and the otherexemplified embodiments and embodiments of the semiconductor laser lightsource have e.g. dimensions—in particular lateral dimensions—between 0.1μm and 1000 μm, preferably between 1 μm and 300 μm. Light-diffusingsub-regions 12A having a circular outer contour preferably have adiameter between 1 μm and 50 μm. In the case of light-diffusingsub-regions 12B comprising a rectangular outer contour—in other words,in the case of bar-shaped light-diffusing sub-regions 12B—the shortsides of the rectangle preferably have dimensions between 1 μm and 50 μmand/or the long sides of the rectangle have dimensions between 1 μm and1000 μm, preferably between 5 μm and 300 μm. In particular, the longsides of the rectangle additionally have a longer length—preferably atleast twice the length—than the short sides. In each case, the limitsfor all the aforementioned ranges are to be regarded as being inclusive.

The light-diffusing sub-regions 12 can be produced e.g. by means of wetetching, whereby it is possible to achieve e.g. a shape of thelight-diffusing sub-region 12 which tapers in the vertical direction V,as illustrated by way of example in FIG. 1B with the aid of the firstlight-diffusing sub-region 12A. The light-diffusing sub-regions 12 canalso be substantially cuboidal, as illustrated by way of example withthe aid of the second light-diffusing sub-region 12B. Such a shape canbe achieved e.g. by means of dry etching. Light-diffusing sub-regions 12produced e.g. by etching constitute cavities in the semiconductor body10 and generally comprise an opening at an external surface of thesemiconductor body 10, in the present case at the p-side externalsurface 102B. They are filled in particular with gas, preferably withair.

Alternatively, light-diffusing sub-regions 12 can be produced by meansof a method which is known in principle to the person skilled in the artby the term “stealth dicing”. In the case of this method, thesemiconductor body is illuminated by a focussed laser beam, wherein thefocal point of the laser beam is positioned within the semiconductorlayer stack. The crystal structure of the semiconductor material of thesemiconductor layer stack 110 is changed in this manner in the region ofthe focal point. By means of a relative movement of the laser beam withrespect to the semiconductor body 10, a light-diffusing sub-regionhaving the desired shape and size can be produced in this manner. Inparticular, light-diffusing sub-regions 12 which are produced by meansof a stealth dicing method comprise semiconductor material having adefect structure consisting of a multiplicity of bubble-shaped hollowspaces, as indicated for the third sub-region 12C in FIG. 1B.

Preferably, a main extension plane E of the light-diffusing structures12 extends at an angle with respect to the main extension direction S ofthe waveguide ridge 114. The waveguide ridge 114 and the main extensionplane E are, in other words, preferably not in parallel with oneanother. For example, the main extension plane E extends in parallelwith the vertical direction V. In this case, the main extension plane Eis the plane which is established by the two directions in which thelight-diffusing sub-region 12 has its two largest dimensions. For thesecond light-diffusing sub-region 12B, it is indicated in FIGS. 1A and1B.

In the case of the present first exemplified embodiment, thelight-diffusing sub-regions have different extensions in the verticaldirection V. For example, the first light-diffusing sub-region 12Aextends completely in the p-type layer 113, the second light-diffusingsub-region 12B extends starting from the p-type layer 113 into theactive layer 112, and the third light-diffusing sub-region 12C extendsstarting from the p-type layer 113 through the active layer 112 into then-type layer 111.

In the vertical direction V—e.g. as seen in a plan view of thedecoupling surface 101—the first, the second and the thirdlight-diffusing sub-regions 12A, 12B, 12C overlap in this manner only inpart. As seen in a plan view of the p-side external surface 102B, theyare in this case laterally spaced apart from the waveguide ridge 114.

In the case of one variant of the first exemplified embodiment, thelight-diffusing sub-regions 12 do not extend from the p-side externalsurface 102B but rather from the n-side external surface 102C into thesemiconductor body 10. This variant is indicated in FIG. 1B by thesub-region 12 shown by the broken line. In the case of this variant, thelight-diffusing sub-regions are contained e.g. completely in the n-typelayer 111. In this case, they can also be arranged underneath thewaveguide ridge 114. For example, they are produced by the stealthdicing method explained above.

FIG. 2 illustrates a schematic plan view of a semiconductor body 10 of alaser light source in accordance with a second exemplified embodiment.

The basic structure of the semiconductor body 10 corresponds to that ofthe first exemplified embodiment. However, in the case of the presentsecond exemplified embodiment the light-diffusing sub-regions 12 arearranged at the decoupling surface 101 and at the opposite transverselateral surface 103 of the semiconductor body 10. In contrast thereto,the light-diffusing sub-regions 12 in the case of the first exemplifiedembodiment are spaced apart from the lateral surfaces (decouplingsurface 101, longitudinal lateral surfaces 102A and transverse lateralsurface 103) of the semiconductor body 10.

For example, the light-diffusing sub-regions 12 in the case of thesecond exemplified embodiment extend from the p-type layer 113 into thesemiconductor layer stack 110 and in particular into the active layer112 or extend through same. Alternatively, the light-diffusingsub-regions 12 can also extend from the n-side surface 12 in thevertical direction V into the semiconductor body 10 and can extend e.g.completely within the n-type layer 111.

The light-diffusing sub-regions 12 are preferably produced before thedecoupling surface 101 and the transverse lateral surface 103 of thesemiconductor body 10 are exposed, preferably by means of the stealthdicing method described above. The decoupling surface 101 and thetransverse lateral surface 103 are exposed e.g. by means of a breakingmethod. By means of the light-diffusing sub-regions 12 arranged directlyat the decoupling surface 101 or the transverse lateral surface 103, theposition and shape of the breaking edges can be advantageouslyinfluenced.

The light-diffusing sub-regions 12 are laterally spaced apart from thewaveguide ridge 114. In this case, in particular, the lateral spacedinterval D is the spaced interval perpendicular to the main extensiondirection S of the waveguide ridge 114 as seen in a plan view of thep-side external surface 102B. For example, the lateral spaced intervalis less than 20 μm, preferably less than 5 μm and particularlypreferably less than 2 μm. In one embodiment, it is greater than 0.5 μm.

By means of such spaced intervals, the light-diffusing structures 12 areparticularly well suited for suppressing the emission of laser modes ofhigher order than the fundamental mode from the decoupling surface 101.The laser light source makes use of the different spatial intensitydistribution of the different modes within the semiconductor body 10.

For this purpose, the light-diffusing sub-regions 12 diffuse laserradiation 22 of these modes e.g. in the direction towards thelongitudinal lateral surfaces 102A which are perpendicular to thedecoupling surface 101. In addition, in the case of this and theremaining exemplified embodiments, the light-diffusing sub-regions 12can diffuse electromagnetic radiation generated by the active layer 112in further directions, e.g. in the direction towards the p-side externalsurface 102B, the n-side external surface 102C.

FIG. 3A illustrates a semiconductor body 10 of a laser light source inaccordance with a third exemplified embodiment in a schematic plan view.FIG. 3B illustrates the semiconductor body 10 in a schematiccross-section in the section plane B-B and FIG. 3C illustrates thesemiconductor body 10 in a schematic cross-section in the sectionalplane C-C.

In the case of this and the preceding exemplified embodiments, thewaveguide ridge 114 of the semiconductor layer stack 110 rises in thevertical direction V beyond regions of the p-type layer 113 whichlaterally adjoin it, so that it constitutes a protrusion in the p-sideexternal surface 102B. In the case of the present third exemplifiedembodiment, the light-diffusing sub-regions 12 are likewise formed asprotrusions of the p-type layer 113, like the transverse ridges 120A, orthey are applied onto a surface of the p-type layer 113, like thetransverse ridges 120B.

The transverse ridges 120A, 120B have a main extension direction Q whichin the present case as seen in a plan view of the p-type layer 113extends perpendicularly with respect to the main extension direction Sof the waveguide ridge 114. In the present case, the main extensionplane of the transverse ridges 120A or 120B coincides with the sectionalplanes B-B or C-C respectively.

The transverse ridges 120A are produced in particular by means of astructuring method, in which the surface of the p-type layer 113 isstructured—e.g. by means of dry etching, wet etching and/or selectiveepitaxial growth—for forming the waveguide ridge 114 and the firsttransverse ridges 120A.

The second transverse ridges 120B are produced e.g. by applying amaterial onto the p-side external surface 102B, which material isdifferent from the semiconductor material of the p-type layer 113.

In the case of one variant of this exemplified embodiment, all of thetransverse ridges 120A, 120B are formed by structuring the p-type layer113. In the case of an alternative variant, all of the transverse ridges120A, 120B are formed by applying a material, which is different fromthe semiconductor material of the p-type layer, onto the p-type layer113.

In the case of a further variant, the refractive index of the transverseridges 120A, 120B is different from the refractive index of the p-typelayer 113; in particular, it is lower than the refractive index of thep-type layer 113. This can be achieved e.g. by means of an ionimplantation method. The refractive index of p-GaN can be lowered e.g.in particular by implantation of protons (H⁺), from 2.46 to 2.26.

In the case of this variant, the transverse ridges 120A, 120B are notnecessarily formed as protrusions of the p-type layer 113. Instead, theycan extend—in particular in an analog manner to the rectangularlight-diffusing sub-regions 12B of the first exemplifiedembodiment—towards the n-side external surface 102C at least into thep-type layer 113 or through same.

In the case of one development of this exemplified embodiment or one ofthe other embodiments of the semiconductor laser light source, a currentpath can also be defined through the semiconductor layer stack 110 inparticular by means of ion implantation and/or an index guidance of thecoherent portion 21 of the electromagnetic radiation can be achieved bymeans of a refractive index change on both sides of the waveguide ridge114. In order to define a current path, e.g. n-type substances such asSi, p-type substances, such as Mg, Zn, Be and/or insulating substances,such as B, He, N, H, can be implanted.

In the case of one further variant of the third exemplified embodiment,more than two transverse ridges 120A, 120B can also follow one anotherin the main extension direction S of the waveguide ridge 114. In thecase of a preferred development of this variant, the transverse ridges120A, 120B which follow one another in this direction are arrangedperiodically. In particular, they form a distributed Bragg reflector(DBR). In particular, the spaced intervals and dimensions of thetransverse ridges 120A, 120B are selected such that the distributedBragg reflector has its highest level of reflectivity for a wavelength λof the coherent portion 21 of the electromagnetic radiation emitted bythe semiconductor layer stack 110. This is also defined as a “λ/4”configuration.

In the case of this and the other exemplified embodiments, thesemiconductor body 10 expediently comprises an electrode 140 forelectrically connecting the semiconductor layer stack 110. A passivation130 is preferably arranged between the electrode 140 and the p-typelayer 113. The passivation 130 comprises an opening which leaves thewaveguide ridge 114 open.

In this manner, the waveguide ridge 114 is electrically contacted bymeans of the electrode 140, in particular the electrode 140 adjoins thep-type layer 113 in the region of the waveguide ridge 114. In the caseof the present exemplified embodiment, regions of the p-type layer 113which are arranged laterally of the waveguide ridge and are covered bythe electrode 140 in plan view are spaced apart from the electrode 140.For the sake of clarity, the electrode 140 and the passivation 130 arenot indicated in the plan view of FIG. 3A.

FIGS. 4A and 4B illustrate a schematic cross-section (FIG. 4A) and aschematic plan view (FIG. 4B) of a semiconductor body 10 of asemiconductor laser light source in accordance with a fourth exemplifiedembodiment.

The semiconductor body 10 comprises first light-diffusing sub-regions12A which extend from the p-side external surface 102B into the p-typelayer 113 of the semiconductor layer stack 110, through the active layer112 and into the n-type layer 111. In this case, their main extensionplane E is, in contrast to e.g. the first exemplified embodiment, not inparallel with the vertical direction V but instead extends in aninclined manner with respect to this direction. In particular, the firstlight-diffusing sub-regions 12A are formed in such a manner that, in theprogression from the n-type layer 111 towards the p-type layer 113, theyrun laterally up to the waveguide ridge 114.

In addition, the semiconductor body 10 in accordance with the fourthexemplified embodiment contains second light-diffusing sub-regions 12Bwhich extend starting from the n-side external surface 102C—opposite tothe waveguide ridge 114—of the n-type layer 111 into the semiconductorbody 10. In particular, they run obliquely up to the active layer 112but extend in particular completely within the n-type layer 111. Theyextend e.g. over at least 50% of the layer thickness, that is to say,the extension in the vertical direction V, of the n-type layer 111. Themain extension planes E of the second light-diffusing sub-regions extendin each case at an angle, i.e. in particular not in parallel with thevertical direction V, but preferably in parallel with the normal vectorN onto the decoupling surface 101 provided for decoupling the coherentportion 21 of the electromagnetic radiation.

In the present case, the first light-diffusing sub-regions are laterallyspaced apart from the waveguide ridge 14. In contrast, as seen in a planview of the p-side external surface 102B at least one secondlight-diffusing sub-region 12B overlaps with the waveguide ridge 114.

The light-diffusing sub-regions 12A, 12B are produced e.g. by means ofcuts in the semiconductor body 10. The cuts can be produced e.g. bymeans of reactive ion etching. In the present case, the light-diffusingsub-regions 12A, 12B extend from the decoupling surface 101 to theopposite transverse lateral surface 103 over the entire length of thesemiconductor body 10.

The first light-diffusing sub-regions 12A are particularly well suitedfor improving the beam quality in the lateral direction, that is to say,in the main extension plane of the active layer 112. The secondlight-diffusing sub-regions 12B are particularly well suited forimproving the beam quality of the semiconductor laser light source inthe vertical direction V.

Each light-diffusing sub-region 12A, 12B is provided in order to directelectromagnetic radiation, which is generated by the active layer 112,towards an external surface or a plurality of external surfaces—e.g. thelongitudinal lateral surfaces 102A, the p-side external surface 102Band/or the n-side external surface 102C—which are different from thedecoupling surface 101 and are inclined with respect thereto.

FIG. 5A illustrates a semiconductor body of a semiconductor laser lightsource in accordance with a fifth exemplified embodiment. FIG. 5Billustrates a schematic cross-section of the semiconductor body 10 ofFIG. 5A in the sectional plane B-B.

As in the case of the preceding exemplified embodiments, thesemiconductor body 10 comprises a semiconductor layer stack 110 havingan n-type layer 111, an active layer 112 and a p-type layer 113. In thiscase, the p-side surface 102B of the p-type layer 113 is structured forforming a waveguide ridge 114.

As in the case of other exemplified embodiments, the main extensiondirection S of the waveguide ridge coincides in particular with thenormal vector N onto the decoupling surface 101 of the semiconductorbody 10 which is provided for decoupling a coherent portion 21 of theelectromagnetic radiation generated by the active layer 112.

In the case of the present fifth exemplified embodiment, thesemiconductor body 10 comprises a light-diffusing sub-region 12 whichhas a main extension plane E which extends in parallel with the verticaldirection V and obliquely with respect to the main extension direction Sof the waveguide ridge 114. In the present case, the main extensionplane E coincides with the section plane B-B of FIG. 5B.

The light-diffusing sub-region 12, as seen in a plan view of its mainextension plane E (and in the present case also in a plan view of thedecoupling surface 101) has a U-shaped configuration. In this case, theopening of the U-shape faces towards the p-side external surface 102B,the limbs of the U-shape extend preferably in parallel with the verticaldirection V.

Preferably, the light-diffusing sub-region 12 extends from the p-sidesurface 102B of the semiconductor layer stack 110 and at a lateralspaced interval D from the waveguide ridge 114 into the p-type layer113, through the active layer 112 and into the n-type layer 111. In then-type layer, the light-diffusing sub-region 12 comprises e.g. a kink ora bend and extends through underneath the waveguide ridge 114. In thefurther progression, it has a further kink or bend so that it extends onthe opposite side of the waveguide ridge 114, again laterally spacedapart therefrom—in particular likewise by the spaced interval D—throughthe active layer 112 and the p-type layer 113 to the p-side surface 102Bof the semiconductor layer stack 110. In this manner, thelight-diffusing sub-region 12 encloses a section 1120 of the activelayer 112.

Preferably, a spaced interval of the light-diffusing sub-region 12 fromthe decoupling surface 101 is less than the spaced interval of thelight-diffusing sub-region 12 from the opposite, in particularmirror-coated transverse lateral surface of the semiconductor body 110.The spaced interval last referred to is preferably at least twice aslarge, particularly preferably four times as large, as the spacedinterval of the light-diffusing sub-region 12 with respect to thedecoupling surface 101. In this manner, a particularly large amount ofelectromagnetic radiation from parasitic laser modes can advantageouslybe decoupled and optionally supplied to a photodiode.

The extension of the light-diffusing sub-region 12 perpendicular to itsmain extension plane E is preferably at the most half, particularlypreferably at the most 20%, of its largest extension in the mainextension plane E. In other words, the light-diffusing sub-region 12constitutes a diagonally extending, light-diffusing wall within thesemiconductor body 10 which is “pierced” by the waveguide ridge 114. Forexample, as seen in a plan view of the p-side external surface 102B thewall has an extension between 5 μm and 500 μm in parallel with its mainextension plane E and has an extension between 1 μm and 50 μmperpendicular to the main extension plane E, wherein in each case thelimits are to be regarded as being inclusive. In this case, theextension in parallel with the main extension plane E is preferablylarger than the extension perpendicular thereto, in particular at leasttwice as large.

FIG. 5C illustrates a variant of the semiconductor body in accordancewith the fifth exemplified embodiment in a schematic sectional view inthe sectional plane B-B of FIG. 5A.

Instead of an individual, U-shaped, light-diffusing sub-region 12, inthe case of this variant two first light-diffusing sub-regions 12A areformed which extend completely within the p-type layer 113 and arelaterally spaced apart from the waveguide ridge 114 by a spaced intervalD. Arranged in the vertical direction V below the waveguide ridge 114 isa second light-diffusing sub-region 12B which extends completely withinthe n-type layer 111 and, as seen in a plan view of the p-type layer113, overlaps with the waveguide ridge 114 and the first light-diffusingsub-regions 12A. The outer contours—facing away from the waveguide ridge114—of the first light-diffusing sub-regions 12A and of the secondlight-diffusing sub-region 12B are, particularly in this plan view,flush with one another.

The light-diffusing sub-regions in accordance with this variant can beproduced in a particularly simple manner by structuring starting fromthe p-type layer 113 and starting from the n-type layer 111. In contrastthereto, the production of the light-diffusing sub-region of the fifthexemplified embodiment in accordance with the FIGS. 5A and 5B is morecomplex—production can be effected by means of the stealth dicing methodwhich is already explained in greater detail above. However, by means ofthis light-diffusing sub-region 12 it is possible to achieveparticularly effective diffusion of a fraction of the electromagneticradiation which is undesired for decoupling at the decoupling surface101.

The portion—extending in the n-type layer 111—of the light-diffusingsub-region 12 of the fifth exemplified embodiment, or the secondlight-diffusing sub-region 12B of the variant of the fifth exemplifiedembodiment extend preferably over 10% or more, particularly preferablyover 30% or more, in particular over 50% or more of the thickness of then-type layer 111.

FIG. 6 illustrates a schematic perspective view of a semiconductor laserlight source in accordance with a sixth exemplified embodiment. Thesemiconductor laser light source in accordance with the present sixthexemplified embodiment comprises a semiconductor body 10 which isconstructed in the manner as described in conjunction with the fifthexemplified embodiment with reference to FIGS. 5A and 5B or with thevariant of the fifth exemplified embodiment with reference to FIGS. 5Aand 5C.

In addition, the semiconductor laser light source in accordance with thesixth exemplified embodiment comprises a photodiode 13. In the presentcase, the photodiode 13 is arranged next to a longitudinal lateralsurface 102A of the semiconductor body 10. The light-diffusingsub-region 12 deflects a portion 22 of the electromagnetic radiationgenerated by the active layer 112 in the direction of the longitudinallateral surface 102A, where it is decoupled at least partially from thesemiconductor body 10 and coupled into the photodiode 13.

FIG. 7 illustrates a schematic cross-section of a semiconductor laserlight source in accordance with a seventh exemplified embodiment.

The semiconductor laser light source in accordance with the seventhexemplified embodiment comprises a semiconductor body 10 having alight-diffusing sub-region 12 which extends completely within the n-typelayer 111 and has the shape of a straight prism having a triangular basesurface. The normal vectors N on the triangular base surface and on thedecoupling surface 101 are parallel, so that the prism extendslongitudinally of the waveguide ridge 114 and, as seen in the plan viewof the p-side external surface, preferably overlaps therewith.

As in the case of the preceding exemplified embodiment, thelight-diffusing sub-region 12 diffuses a portion 22 of theelectromagnetic radiation generated by the semiconductor layer stack 110towards a longitudinal lateral surface 102A, where it is at leastpartially decoupled and is at least partially coupled into thephotodiode 13 arranged adjacent to the longitudinal lateral surface102A.

Such a prismatic light-diffusing sub-region 12 is particularly wellsuited for irradiating a photodiode 13 arranged on the longitudinalside.

FIG. 8 illustrates a schematic cross-section of a semiconductor laserlight source in accordance with an eighth exemplified embodiment.

The light-diffusing sub-regions 12A, 12B of the semiconductor body 10 ofthe semiconductor laser light source in accordance with the eighthexemplified embodiment are formed in a similar manner to those of thesemiconductor body 10 in accordance with the fourth exemplifiedembodiment (see FIGS. 4A and 4B).

However, in the case of the present exemplified embodiment, the firstlight-diffusing sub-regions 12A, in the progression from the n-typelayer 111 to the p-type layer 112 of the semiconductor layer stack 110,do not run up to the waveguide ridge 114 but rather run away therefrom.They are laterally spaced apart from the waveguide ridge 114 and, asseen in a plan view of the p-side external surface of the semiconductorbody 10, overlap with a photodiode 13 which is arranged laterally nextto the waveguide ridge 14 on the p-side external surface 102B of thesemiconductor body 10.

In addition, the semiconductor body 10 also comprises secondlight-diffusing sub-regions which are located completely within then-type layer 110 and have main extension planes E which extend obliquelywith respect to the vertical direction V and in parallel with the normalvector N onto the decoupling surface 101 (perpendicular the drawingplane in FIG. 8). As seen in a plan view of the p-side external surface102B of the semiconductor body 10, the second light-diffusingsub-regions 12B likewise overlap with the photodiode 13 applied on thisexternal surface 102B. In this manner, a portion 22 of theelectromagnetic radiation generated by the active layer 112 is directedin a particularly efficient manner towards the p-side external surface102 and in particular towards the photodiode 13.

FIG. 9 illustrates a schematic perspective view of a semiconductor laserlight source in accordance with a ninth exemplified embodiment. Thesemiconductor laser light source in accordance with this exemplifiedembodiment corresponds substantially to that of the sixth exemplifiedembodiment which is described above in conjunction with FIG. 6.

In contrast to the sixth exemplified embodiment, in the case of thepresent ninth exemplified embodiment the longitudinal lateral surface102A which faces towards the photodiode 13 is provided withlight-diffusing structures 160. For example, a portion of thelongitudinal lateral surface 102A which as seen in a plan view of thelongitudinal lateral surface 102A overlaps with the photodiode 13 isprovided with the light-diffusing structures 160, whereas a portionwhich is not covered by the photodiode is free of light-diffusingstructures. Alternatively, the entire longitudinal lateral surface 102Acan also be provided with the light-diffusing structures.

The light-diffusing structures are either macroscopic structures,wherein in the present case “macroscopic structures” are understood tomean that their dimensions at least in one dimension are larger than 10μm, preferably larger than 100 μm. However, the light-diffusingstructures can also be formed by roughening which is formed in such amanner that it is suitable for diffusing electromagnetic radiationhaving a wavelength of an intensity maximum of the coherent portion 21.For example, the roughening therefore contains structure units havinglateral dimensions between 100 nm and 1 μm, wherein in each case thelimits are to be regarded as being inclusive.

FIG. 10 illustrates a schematic cross-section of a semiconductor laserlight source in accordance with a tenth exemplified embodiment.

It comprises a semiconductor body 10 whose longitudinal lateral surfaces102A are chamfered in a p-side edge region for forming light-diffusingsub-regions 12. The oblique sub-regions of the longitudinal lateralsurfaces 102A extend in the present case from the p-side externalsurface 102B of the semiconductor body 10 in the vertical direction Vbeyond the active layer 112 into the n-type layer 111. By means of theselight-diffusing sub-regions 112, a portion 22 of the electromagneticradiation generated by the active layer 112 is directed in the directionof the n-side external surface 102C of the semiconductor body. Arrangedon this n-side external surface 102C or above this n-side externalsurface 102C is a photodiode 13 which is formed for receiving at least aportion of this electromagnetic radiation 22.

FIG. 11 illustrates a schematic plan view of a semiconductor laser lightsource in accordance with an eleventh exemplified embodiment. FIG. 14illustrates a schematic cross-section of the semiconductor laser lightsource of FIG. 11 in the sectional plane B-B.

In the case of the present semiconductor laser light source, thephotodiode 13 is formed so as to be integrated into the semiconductorbody 10.

For example, a section 1120 of the active layer 112 which, as seen in aplan view of the p-side external surface 102B, overlaps with thewaveguide ridge 114 is formed for generating the electromagneticradiation and in particular the coherent portion 21 of theelectromagnetic radiation. This section 1120 is contacted by theelectrode 140, as described e.g. in conjunction with the thirdexemplified embodiment.

A further section of the active layer 112 is electrically separated fromthe section 1120 by means of an isolator 170 and is electricallycontacted by a further electrode 150. For example, the passivation 130which is applied onto the p-side external surface 102B extends as anisolator 170 into a trench which is formed longitudinally of thewaveguide ridge 114 in the semiconductor layer stack 110 and whichseparates the active layer 112.

The semiconductor body 10 comprises first light-diffusing structures 12Awhich are formed in order to direct electromagnetic radiation, which isgenerated by the section 1120 of the active layer 112, in the directionof the longitudinal lateral surfaces 102A, so that it impinges inparticular upon the monolithically integrated photodiode 13.

Second light-diffusing sub-regions 12B are formed in the n-type layer111 and, as seen in a plan view of the p-side external surface 102B,overlap in particular with the photodiode 13. In an expedient manner,they are formed in order to direct electromagnetic radiation generatedby the active layer 112 in the direction of the p-side external surface102B, so that it impinges in particular upon the portion of the activelayer 112 separated for forming the photodiode 13.

In the case of the eleventh exemplified embodiment, the photodiodeextends in the main extension direction S of the waveguide ridge 114over a large part of the length of the semiconductor body 10, e.g. over80% or more of the length of the semiconductor body 10.

FIG. 12 illustrates a schematic plan view of a semiconductor laser lightsource in accordance with a twelfth exemplified embodiment.

The semiconductor laser light source in accordance with the presenttwelfth exemplified embodiment corresponds to that of the eleventhexemplified embodiment, however the photodiode 13 does not extend over alarge part of the length of the semiconductor body 10 but rather it isformed in the vicinity of the decoupling surface 101. In particular, inthe case of the present twelfth exemplified embodiment, the spacedinterval of the photodiode 13 from the transverse lateral surface 103which is opposite to the decoupling surface 101 is preferably at leasttwice as large, particularly preferably at least four times as large asthe spaced interval of the photodiode 13 from the decoupling surface101.

FIG. 13 illustrates a section of a longitudinal sectional view whichextends in the active layer 112 through the semiconductor body 10 of alaser light source in accordance with a variant of the eleventh andtwelfth exemplified embodiments. In the case of this variant, thephotodiode 13 does not have a rectangular or square geometry as in thecase of the eleventh or twelfth exemplified embodiment, but rather isformed as an irregular polygon.

The semiconductor laser light sources in accordance with the first tofifth exemplified embodiments can likewise each comprise a photodiode 13which is arranged e.g. at a longitudinal lateral surface 102A, on thep-side external surface 102B or the n-side external surface 102C of thesemiconductor body 10 or is adjacent to one of these surfaces.

In the case of each exemplified embodiment, the semiconductor laserlight source can comprise an electrical circuit which is electricallyconnected to the semiconductor layer stack 110 and to the photodiode 13and is formed in order, during operation of the semiconductor laserlight source, to evaluate an electrical signal of the photodiode 13 andto control an operating current through the semiconductor layer sequence110 in dependence upon the signal of the photodiode 13.

The different embodiments of the light-diffusing sub-regions 12, 12A,12B, 12C of the individual exemplified embodiments can be combinedtogether in a semiconductor body 10.

Moreover, the invention is also not limited to the exemplifiedembodiments by the description thereof. Rather, the invention includesany new feature and any combination of features, in particular anycombination of features in the claims and any combination of features inthe exemplified embodiments, even if this combination is not explicitlystated in the claims or exemplified embodiments.

This patent application claims the priority of German patent application102012103549.0, the disclosure content of which is hereby incorporatedby reference.

1. Semiconductor laser light source comprising an edge-emittingsemiconductor body which contains a semiconductor layer stack having ann-type layer, an active layer and a p-type layer which is formed forgenerating electromagnetic radiation which comprises a coherent portion,wherein the semiconductor laser light source is formed for decouplingthe coherent portion of the electromagnetic radiation from a decouplingsurface of the semiconductor body which is inclined with respect to theactive layer, the semiconductor body comprises a further externalsurface which is inclined with respect to the decoupling surface, andthe semiconductor body comprises at least one light-diffusing sub-regionwhich is provided in order to direct a portion of the electromagneticradiation generated by the semiconductor layer stack in the directiontowards the further external surface.
 2. Semiconductor laser lightsource according to claim 1, wherein the at least one light-diffusingsub-region extends starting from the n-type layer or starting from thep-type layer into the active layer or through the active layer. 3.Semiconductor laser light source according to claim 1, wherein thesemiconductor body comprises a waveguide ridge which is formed by thesemiconductor layer stack and has a main extension direction whichextends in the direction of a normal vector onto the decoupling surface.4. Semiconductor laser light source according to claim 3, wherein the atleast one light-diffusing sub-region extends at least in the p-typelayer and is laterally spaced apart from the waveguide ridge in theregion of the p-type layer.
 5. Semiconductor laser light sourceaccording to claim 1, which comprises a first and a secondlight-diffusing sub-region, wherein the first light-diffusing sub-regionextends at least in the n-type layer, the second light-diffusingsub-region extends at least in the p-type layer and, as seen in a planview of the decoupling surface, the first and the second light-diffusingsub-regions do not overlap or overlap only partially in a verticaldirection, in which the n-type layer, the active layer and the p-typelayer follow one another.
 6. Semiconductor laser light source accordingto claim 1, wherein in order to form the at least one light-diffusingsub-region a cavity is formed in the semiconductor body. 7.Semiconductor laser light source according to claim 1, wherein the atleast one light-diffusing sub-region is formed by means of a materialcomposition and/or crystal structure in the semiconductor body whichdeviate from the material composition or crystal structure which aregion of the semiconductor body adjoining the sub-region comprises. 8.Semiconductor laser light source according to claim 3, wherein the atleast one light-diffusing sub-region is formed by means of a transverseridge which is applied at the side of the waveguide ridge onto thesemiconductor layer stack or is formed by the semiconductor layer stack.9. Semiconductor laser light source according to claim 8, wherein therefractive index of the transverse ridge is different from therefractive index of the waveguide ridge.
 10. Semiconductor laser lightsource according to claim 1, wherein the at least one light-diffusingsub-region has a main extension plane which extends in an inclinedmanner with respect to a vertical direction, in which the n-type layer,the active layer and the p-type layer follow one another. 11.Semiconductor laser light source according to claim 1, wherein the atleast one light-diffusing sub-region has a main extension plane whichextends in an inclined manner with respect to a normal vector onto thedecoupling surface.
 12. Semiconductor laser light source according toclaim 1, wherein the light-diffusing sub-region is formed in a u-shapedmanner as seen in a plan view of the decoupling surface such that itencloses a section of the active layer.
 13. Semiconductor laser lightsource according to claim 1, comprising a photodiode which is arrangedon or above the further external surface of the semiconductor body. 14.Semiconductor laser light source according to claim 1, comprising aphotodiode which is integrated monolithically into the semiconductorbody.
 15. Semiconductor laser light source according to claim 14,wherein a material having a refractive index which is larger than arefractive index of the photodiode and than a refractive index of theactive layer is arranged between the photodiode and a section of theactive layer adjoining the photodiode.
 16. Semiconductor laser lightsource according to claim 13, wherein the photodiode is arrangedadjacent to a longitudinal lateral surface of the semiconductor body.17. Semiconductor laser light source according to claim 13, wherein thesemiconductor body comprises a waveguide ridge, and wherein thephotodiode is arranged laterally next to the waveguide ridge on thep-side external surface of the semiconductor body.
 18. Semiconductorlaser light source comprising an edge-emitting semiconductor body whichcontains a semiconductor layer stack having an n-type layer, an activelayer and a p-type layer which is formed for generating electromagneticradiation which comprises a coherent portion, and comprising aphotodiode which is integrated monolithically into the semiconductorbody, wherein the semiconductor laser light source is formed fordecoupling the coherent portion of the electromagnetic radiation from adecoupling surface of the semiconductor body which is inclined withrespect to the active layer, the semiconductor body comprises a furtherexternal surface which is inclined with respect to the decouplingsurface, the semiconductor body comprises at least one light-diffusingsub-region which is provided in order to direct a portion of theelectromagnetic radiation generated by the semiconductor layer stack inthe direction towards the further external surface, and an isolator isarranged between the photodiode and the active layer.